Summary: A quick way to repair ships without having to do so by hand that will also act as a credit-sink of sorts by adding the ability to repair a ship based on catalog features.
The "repair to catalog specs" option would work by checking the blocks on the ship core that are missing from the catalog and replacing them WITHOUT modifying blocks that are in place of the catalog-specified blocks. So if a light hull was blown off by a missile, and the light hull is in the catalog, it would be replaced. If you replaced that light hull with a hardened hull, the repair-to-spec option would do nothing.
You're charged the cost of the replaced blocks in credits.
This would also mean you could buy a ship as a basic template, add on to it, and repair the ship from the catalog without interfering with your additions. You could then make an additional catalog entry based on your purchased ship + the additions you made so you could have a cheap repair option and a full repair option (basic template you originally purchased versus all the additions in the second catalog entry).
The "repair to catalog specs" option would work by checking the blocks on the ship core that are missing from the catalog and replacing them WITHOUT modifying blocks that are in place of the catalog-specified blocks. So if a light hull was blown off by a missile, and the light hull is in the catalog, it would be replaced. If you replaced that light hull with a hardened hull, the repair-to-spec option would do nothing.
You're charged the cost of the replaced blocks in credits.
This would also mean you could buy a ship as a basic template, add on to it, and repair the ship from the catalog without interfering with your additions. You could then make an additional catalog entry based on your purchased ship + the additions you made so you could have a cheap repair option and a full repair option (basic template you originally purchased versus all the additions in the second catalog entry).